<nav class='toc'>
  {% for section in site.data.nav_docs %}
    <section>
      <h3>{{ section.title }}</h3>
      <ul>
        {% for item in section.items %}
          {% for doc in site.docs %}
            {% assign item_url = item | prepend:"/docs/" | append:".html" %}
            {% if doc.url == item_url %}
            <li>
              <a href={{item_url}}{% if page.url == item_url %} class="active"{% endif %}>
                {{ doc.title }}
              </a>
            </li>
            {% endif %}
          {% endfor %}
        {% endfor %}
      </ul>
    </section>
  {% endfor %}
</nav>
